BT is a precursor to butanetrioltrinitrate (BTTN), which is used as an energetic plasticizer in tactical rocket motor propellants, and some pharmaceutical compounds or agricultural chemicals. Multiple methods of synthesizing BT are known, such as the hydroformylation of glycidol and subsequent reduction of the reaction product, the catalytic hydrogenation of malic acid, and biotechnological syntheses using genetically engineered bacteria. Another method of synthesizing BT includes reducing a dialkyl malate with sodium borohydride. However, in addition to producing BT, the latter reaction produces borate salts as an impurity. The borate salts bind to the BT, forming a complex, which prevents the isolation of pure BT. To remove the borate salts, large volumes of an alcohol solvent are used in a distillation process. However, the distillation involves using large amounts of a flammable and toxic material (the alcohol solvent), and is labor intensive. While the BT obtained from the distillation has an organic purity of greater than 98%, the resulting BT includes inorganic impurities, such as the borate salts.
Ion exchange chromatography has been used to remove the borate salts. However, the boron-specific ion exchange resins do not have the capacity to remove large amounts of boron. In addition, the boron-specific ion exchange resins do not effectively remove the borate salts in the presence of a competitive binding agent, such as BT.
It would be desirable to be able to isolate and purify BT using a process capable of removing large quantities of borate salts using a relatively inexpensive and non-toxic starting material. The purified BT would be free of inorganic impurities.